Cessna 120-140 Association

8164 wrote: ↑Fri Jun 21, 2024 2:30 pm My first post in this group. Just bought a 1947 140, though I also owned a '46 120 for several years. I'm not new to the type and, though I'm not an A&P, I worked many years as a mechanic's assistant on warbirds and Ive worked on my planes for a long while, under the supervision of A&Ps and I/As.

Having said that, I thoroughly searched through this forum (and the many, many discussion of the Scott 3200 setup) and I cannot find this piece of information:

1. What is the torque value for the four (4) AN4 bolts that hold the two wheel halves together on our 140's (using a Scott 3200)?To be perfectly honest I can't find anything that discusses torque value for the AN4-7A bolts that are utilized to bolt the two wheel halves together. I even looked in my old US Army L-19/0-1 manuals, and the publication only says to tighten the nuts securely without any torque value. Therefore, what my fellow moderator John Cooper has recommended about utilizing the torque chart as found in FAA AC43.13-1b will be a good choice. I agree with the 70 in-lbs as John has stated.

Alaskan Bushwheels (the now owner of the Scott 3200) publishes a 1-sheet instruction which says, "Torque AN4-34A bolts to 120 in-lbs." I'm using the AN4-7A bolts, though I assume that's essentially the same. Is that the torque you folks are using? AN4-7A are the correct bolts for the Scott 3200 as per Scott Aviation. AN4-34A bolts utilized by Alaskan Bushwheels is for a much wider wheel and tire configuration than found on the standard Scott 3200 type wheel, use the AN4-7A bolts.

2. What is the proper inflation of the 2.80x250 tailwheel tire? Alaskan says 25 psi. Other here say 45 psi, still others use 55 psi. I'm curious what the general consensus is.This question comes up from time to time, and it really depends on how much weight is imposed on the tailwheel from the aircraft. What the weight is on my tailwheel assembly for example, is not the same for all aircraft of this series. Items like landing gear extenders and additional equipment adds weight to the airframe that is different from when your aircraft was originally manufactured. Cessna 170's for example, had a placard/decal in the glove box that said used 35 psi in the tailwheel tire. Here's a Scott tire pressure chart from our friends over at the C-170 Association.]



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Thanks!

Marc C. Lee
N2323N

8164 wrote: ↑Tue Jun 25, 2024 8:29 pm I'll try the 75 inch pounds.